This invention relates to systems for the detection of explosives and other controlled substances such as drugs or narcotics as well as other chemicals used in clandestine activities.
Recent terror attacks have changed the dynamics of the explosive detection systems across the globe. Terrorists, acting singly or in concert, instill immense fear and apprehension in civilians and governments alike with their technical knowledge about explosives. In parallel, the world has experienced an increase in the transportation of contraband substances such as drugs or narcotics.
With advances in explosives technology, such as the advent of the plastic explosives, which can be disguised as common items, it is becoming increasingly difficult to detect these substances. The problems that must be overcome in the detection of these substances as well as others, include low vapor pressure of the particular vapors escaping from the particular substance, the search time and the throughput of the various systems, the low concentration of vapor or particulate emissions from the particular substance, isolation of the particular substance with a high degree of reliability, and maintaining the integrity of the systems environment.
Various techniques for detecting substances such as explosives and drugs or narcotics have been developed, ranging from explosives/drug sniffing dogs to highly sophisticated vapor detection devices. Machine detection of the aforementioned substances can be accomplished through non-vapor detection or vapor detection. Non-vapor detection methods include x-ray detection, gamma-ray detection, neutron activation detection and nuclear magnetic resonance detection. These methods of detection are more applicable to the detection of the various substances when the substances are concealed and are carried or associated with non-living items such as baggage as these techniques might pose a threat to living items. Vapor detection methods include electron capture detection, gas chromatography detection, mass spectroscopy detection, plasma chromatography detection, bio-sensor detection and laser photo-acoustic detection. These methods of detection are more applicable to the detection of substances that are concealed and associated with living specimens.
Conventional systems tend to be large and immobile. Further, current systems can require users to manually apply toxic chemicals as testing agents. As a result, conventional systems are not mobile and hard to use. Hence, their adoption for field use has been limited.